Structural health monitoring using sprayable paint formulations

• US 9,194,832 B2
• Filed: 09/13/2011
• Issued: 11/24/2015
• Est. Priority Date: 09/20/2010
• Status: Expired due to Fees

• Current Assignee: BAE Systems Plc
• Original Assignee: BAE Systems Plc
• Inventors: Dunleavy, Michael, Dyke, Hazel Anne, Haq, Sajad
• Primary Examiner(s): Kirkland, III, Freddie
• Assistant Examiner(s): Michael, Fredrick
• Application Number:
  US13/702,607
• Publication Number:
  US 20130312535A1
• Time in Patent Office: 1,533 Days
• Field of Search: 526/319, 526/329.7, 526/348.8, 723/52, 723/63, 723/792, 723/796, 73/540.1, 73/544.3, 738/613.55, 738/642.2, 738/642.3, 738/66, 737/76
• US Class Current: 1/1
• CPC Class Codes: B01F 23/56 by introducing solids in liquids, e.g. dispersing or dissolving
• CPC Class Codes: B01F 31/80 Mixing by means of high-frequency vibrations above one kHz, e.g. ultrasonic vibrations
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: G01M 5/0033 by determining damage, crack or wear
• CPC Class Codes: G01M 5/0041 by determining deflection or stress
• CPC Class Codes: G01M 5/0083 by measuring variation of impedance, e.g. resistance, capacitance, induction
• CPC Class Codes: G01N 27/041 of a solid body
• CPC Class Codes: G01N 33/32 Paints; inks investigating resistance to the weather, to corrosion, to light G01N17/00

Abstract

The structural health of a structure such as an aircraft is monitored by spraying a paint formulation containing a loading of carbon nanoparticles to provide a paint layer forming part of a paint system. The paint layer forms a smart skin whose electrical properties may be monitored to determine structural health.

Claims

1. A method of monitoring structural health of a structure, the method comprising:

applying a sonification treatment to a paint formulation containing a dispersion of carbon nanoparticles to assist dispersion of said carbon nanoparticles;

spraying said paint formulation containing said dispersion of carbon nanoparticles to provide a paint layer on said structure to form part of a durable paint system; and

monitoring an electrical characteristic of said paint layer to thereby determine an indication of the structural health of said structure in a region of said paint layer.

2. A method according to claim 1, wherein the layer comprises:

a top coat of the paint system.

3. A method according to claim 1, wherein the layer comprises:

a primer layer of the paint system.

4. A method according to claim 1, wherein said

paint formulation comprises:

a two or more part polyurethane paint.

5. A method according to claim 1, wherein said paint formulation comprises:

an epoxy system.

6. A method according to claim 1, comprising:

adding a solvent to the paint formulation to assist dispersion of said carbon nanoparticles.

7. A method according to claim 1, wherein said sonification treatment is effected over a plurality of spaced time intervals.

8. A method according to claim 1, comprising:

after said sonification treatment, allowing the formulation to cool prior to addition of a hardener before spraying.

9. A method according to claim 1, wherein said carbon nanoparticles comprise:

carbon nanotubes.

10. A method according to claim 9, wherein said carbon nanotubes have a mean length of between 0.05 nm and 20 nm.

11. A method according to claim 9, wherein a mean diameter of the carbon nanotubes lies in a range of 7 nm to 30 nm.

12. A method according to claim 9, wherein the carbon nanotubes have a mean number of walls of between 3 and 30.

13. A method according to claim 9, wherein a percentage loading of carbon nanotubes in the paint layer is between 1% and 20% by weight.

14. A method according to claim 1, wherein a thickness of the paint layer lies within a range of 10 μ

m to 300 μ

m.

15. A method according to claim 1, wherein a resistivity gauge factor of the paint layer lies within a range of 1 to 1000.

16. A method according to claim 1, comprising:

applying said paint layer as a continuous layer over an extended region to be monitored.